docs: def _allocate_ips_to_nics(self, conf):
          """
          For all the nics of all the domains in the conf that have dynamic ip,
          allocate one and addit to the network mapping
  
          Args:
              conf (dict): Configuration spec to extract the domains from
  
          Returns:
              None
          """
          for dom_name, dom_spec in conf.get('domains', {}).items():
              for idx, nic in enumerate(dom_spec.get('nics', [])):
                  if 'ip' in nic:
                      continue
                  net = self._get_net(conf, dom_name, nic)
                  if net['type'] != 'nat':
                      continue
  
                  allocated = net['mapping'].values()
                  vacant = _create_ip(
                      net['gw'],
                      set(range(2, 255)).difference(
                          set([int(ip.split('.')[-1]) for ip in allocated])
                      ).pop()
                  )
                  nic['ip'] = vacant
                  self._add_nic_to_mapping(net, dom_spec, nic)